If your son uses any other substances, such as caffine or nicotine they may help him deal with the "side effects".
My best advice is to start with very small amounts several times throughout the day. Have him smoke just one or two hits, then wait for 20 minutes or a half hour before smoking more. Although when smoking the effects can be felt immediately, full onset takes about 15-20 minutes, depending on the weed and the individual. It is easy for an inexperienced user to smoke too much too quickly simply because they haven't really felt the first hit they took yet. A quarter of a joint may be too much too quickly for someone without a tolerence.
Get him a "dugout" and "cigbat". This is a small wooden box that contains a chamber for crushed bud and a little pipe that looks like a cigarette. These are very discrete and allow a patient to take in a small, controlled, amount every few hours throughout the day. I think I heard they were giving these to every new medical cannabis patient in California for a while.
Your son may find that after a few days or a week of taking cannabis is small regular small doses that he doesn't even notice the high, or that it isn't as uncomfortable as he once felt. Most people, when aware of their intake, eventually find the exact amount they need to smoke in a day to relieve their pain while still functioning.
Another idea is to make change the method of consumption. Has he tried edibles? Have him try cannabutter and tincture. Edibles have the added bonus of being extremely safe to carry and consume without police harrassment. Tincture in particular also works almost as fast as smoking when a small amount is held in the mouth for 30 seconds or so.
Marinol is not nearly as safe or effective as cannabis. There is plenty of information out there about it, so you should research and decide for yourself. I believe marinol is mostly on the market because pharmaceutical companies were desperate to find some way to profit from medical cannabis.
The medical cannabis program in New Mexico just a border away is just getting started, but there may be a way for him to get involved when it is more legit. I think it is more likely that Texas will just legalize the stuff rather than start a medical program, but that it still a few years away. I think most people in Texas don't want it to be a crime any more.
Chances are, your son's negative reaction to being high is psychological. You have said that he feels guilt for using drugs, which is completely understandable. There was certainly a time when I thought that pot was the boogy man, and it certainly effected my perception of the high the first few times I tried it, even though it wasn't something I believed anymore. If this is the case, he will probably learn to relax and enjoy the high a bit more as time goes on. The fear, at least for me, was in becoming a burn out, but being a stoner doesn't make your a burn out. Thomas Jefferson was a pot head, and so are most of the guys running the computer business these days. Lots of people get stoned every day and go out and accomplish things.
Good luck, I hope everything works out for ya.
